Accelerants for Gainer's Vitamin C/phenidone developer

Peter;

 

I had no way of knowing what anyone here used after the developer. All I wanted to do was bring to your attention an observation that I made with carbonate developers.

 

I'm sure your problem must be due to high activity.

 

Maybe bicarbonate might be of use.

 

Ron Mowrey

About the question as to why borax usually gives finer grain than carbonate: I can usually tell how visible grain wwill be by how easy it is to tell which is the emulsion side of a negative. The grainier ones have a duller surface. I don't know if it is due to pH or something else. Borax includes combinations of borax and NaOH which are capable of the same pH as carbonate.

 

It may be due to the greater buffer capacity of borax solutions. Plain borax changes pH very little with concentration, so you can get a fairly low pH with a lot of resistance to change.

 

It's certain, as we see from the postings here, that pH is not the only factor in choosing an alkali. It may be the major factor in determining activity and maximum CI, but granularity, resolution and acutance can be different when CI is held constant.

 

I am pretty sure that the difference between borax and TEA is not significant, but sure as I stick my neck out, someone will find otherwise.

Hi, everyone. I'm sorry to enter the thread at so late a stage, but if anyone cares to return to this extremely interesting discussion, here are some practical results I have ended up with.

 

Using the information available on this forum as well as from Pat Gainer's articles, I prepared a concentrate solution of VC and Phenidone. I used glycerine since it is always in stock at a pharmacy near my place. Besides, it's absolutely non-toxic and very cheap, too.

 

I poured 120 ml in a 500 ml beaker and placed in a pot of water to make it float, then began to heat the water. Using a simple 'gunpowder' scale I weighed 12 g VC and 0.25 g Phenidone and added to the glycerine stirring continuously while keeping the water bath just simmering. Both reagents dissolved pretty quickly and without a trace of sediment or solid particles (I didn't use a thermometer, but the glycerine temperature must have been well below 100 deg. C). That's the solution A.

 

As concerns the activator I tried several different combinations including sodium carbonate and a mixture of borax (sodium tetraborate decahydrate) and NaOH in a proportion corresponding to the composition of Kodalk (sodium metaborate tetrahydrate). Most published results indicate that 1 l of a working solution should be made up with 20 ml of the stock solution A + 5 g sodium carbonate (or an equivalent volume of its solution). This typically yields dev times similar to undiluted D76. Since at most times I develop my film at temperatures higher than 20 deg. C / 68F, I tried to formulate the proportions in a manner that would yield times similar to D76 1 + 1.

 

All in all, I ended up with the alkali solution (B) containing 25 g of sodium carbonate in a litre of solution. To make the working solution I take 5 ml A + 50 ml B + 350 ml water. The results are exactly what I want: dev times 10 - 11 min for most 400 ASA films, 7 - 8 min for 100 ASA films. Acutance is excellent, grain pretty low (similar to D76 1+1 or even Xtol), and, what surprises me most, the fogging tendency is nonexistent. Although I haven't used a densitometer, my impression is that the effective film speed is very close to the box figure. Looks like I will have a reliable, long-lasting, clean-working developer of choice for many years to come.

 

Many thanks to all for another interesting thread and a special acknowledgement to Pat Gainer for his personal tutorial and encouragement.

Patrick

 

I think you've rised a valid point - the correlation between pH and grain seems to have a weak dependency with the type of alkali used. The main factor is pH value, and both borax and 'TEA' in my case produces very fine grain with PX.

 

Once, I've added an inordinate ammount (50g/liter) of boric acid to a PA dev, using carbonate as accelerator. Grain was very fine (but also contrast was low, should have developed longer), but the solution was extremelly short lived (possibly due to metal contamination by boric acid impurities), so I gave it up. It was the only time I've been victimized by sudden death!

 

Regarding fog, PX has a very clear base with 'TEA', while Fortepan clearly shows fog (I did a compare with clear film, a test stip that was just fixed). So, there's a dependency on film type.

Tomasz, it's interesting to hear that you had good results with a carbonate-only activator. It's hard to explain the discrepancy between our results. Your carbonate concentration works out to about 1.5g/liter working solution, right? I never tried using as little as that - the lowest carbonate-only solution I tried was about twice as strong. Grain was objectionable and accutance was low, so it seemed like the wrong direction to go. What films have you tried this with?

Regarding pH of a solution, it depends on two things. One is the equillibrium constant of the buffer used, and two is the concentration of the buffer. This latter also includes the capacity of the solution to buffer.

 

Borax buffers at around 10. Solutions of borax gradually increase in pH from 7 to 10 as you add borax until the maximum buffer capacity is reached, and then the pH levels off but capacity increases as you increase the concetration of the borax. D76 is about pH 9 - 10, using borax but at low concentration, so it has low capacity but 'normal' pH.

 

D52, Dektol, has about 20 g/l carbonate and a pH of about 10. That is about medium to normal capacity and normal pH for carbonate.

 

You can raise or lower pH of any of these by adding base or acid respectively. Therefore, addition of hydroquinone, a weak acid, will reduce pH of a poorly buffered solution or one which has little base in it. Sodium Sulfite is a weak base, and so it buffers a developer itself, so at 100 g/l, as in D76, it is both a silver halide solvent (weak) and a buffer (weak).

 

You can add sodium hydroxide to a borax developer and get a high pH of even 12, but it has poor buffering capability and pH will drop more rapidly than expected. Absorption of carbon dioxide from air and the action of oxidizing the developing agents reduces alkalinity by producing protons (acid).

 

That said, if you want a pH of around 9-10 use borates or organic amines with or without sulfite. Adjust pH with a little sodium hydroxide, but not too much.

 

For a pH of 10 - 11, use carbonates mixed with sulfites and bicarbonates with sodium hydroxide to adjust.

 

For a pH of 11 - 12 use a mix of phosphates with sulfite as needed and hydroxide to adjust.

 

2 - 20 g/l of any buffer is weak, 20 - 50 g/l is medium and 50 - 100 g/l is strong buffering. These latter two levels of buffer in developers retain pH the longest. Of course, the levels of buffer depend on solubility in the solvent. Borax compounds are somewhat less soluable than carbonates.

 

That is the general rule I used in designing developer solutions.

 

Much of it came in person from Dick Henn and Grant Haist, two authoritative voices in designing B&W developers.

 

Ron Mowrey

Ron

 

Thanks for the interesting post re buffers.

 

Could you pls comment in the solvent action of organic amines on silver halide?

Jorge;

 

I have limited experience there. Triethanol amine has virtually no solvent activity at all. Benzyl amine is about the same. Ethylene diamine is fairly strong. Its effects are used in the Ektachrome family of Color Developers as per published formulas on the EK site.

 

I guess a generalaziation is that highly substituted amines or aromatic amines such as EDTA, Benzyl Amine, and TEA are not solvents but aliphatic amines are. Examples of those are Ethylene Diamine, Ethyl amine (a gas at room temp IIRC - I would have to look it up).

 

I'll give it more thought and look up some refs.

 

Ron Mowrey

Jorge;

 

Here is my follow up. Ammonia, the simplest 'amine' is a powerful silver halide solvent. Methyl and Ethyl amine as well as Dimethyl and Diethylamine are similar to ammonia in action.

 

In negative processes, I have observed toe sharpening or a threshold speed loss and increases in contrast. Dmax is often increased due to the re-deposition of silver at dmax from solution.

 

Silver halide solvents will also render grains that are difficult to develop, developable. This is another reason you may see dmax go up.

 

In high iodide emulsions, development rate will go up within limits. The solvent action decreases as iodide content goes up. Iodide represses the silver halide action of amines (or any silver halide solvent in fact).

 

Exposure to amine vapors before development can fog emulsions. At very low concentrations, certain amines can supersensitize emulsions, at the cost of high fog. That is actually what may be causing the fog; the increase in speed or a softening of the toe. This is contrary to the above, but remember that this is exposure before development I'm talking about here in this latter case.

 

If you use any volatile amine or ammonia in the dark room be very careful that you don't ruin open packages of paper or film. The vapors are insidious. I have worked in a room mixing fix and blix baths with ammonia, and have seen slight fogging effects on the color paper out on the shelf.

 

That about exhausts my experience with amines. Sulfite and other silver halide solvents such as thiourea and thiocyanate are used more often in developers AFAIK, as they are more controllable. Less volatile and easier to measure out would be the reason, I guess.

 

Ron Mowrey

Vapors from Mothballs also ruins unexposed emulsions; humidity; formaldehyde; car exhaust; vapors from paints too

Ron,

Where did the number 10 come from for the buffering pH of borax? I find in the CRC Handbook of Chemistry and Physics that a 0.01 molal solution (3.8 g/l) has pH of 9.225 at 20 C, and in another table that a 0.10 N solution has pH of 9.2. Again, 50 ml of 0.25 molar borax + 0.9 ml of 0.1 molar NaOH has pH of 9.2. You would have to add 18.3 ml of the NaOH solution to get pH = 10.

Sorry for my imprecision.

 

I was lumping all of the borate alkali buffers together for simplicity. I guess I caused confusion instead. I did say that the range of borate buffering was 9 - 10. Many borax buffered solutions are as you say at 9 - 9.5, but Kodalk buffered solutions are at 10.1 or so.

 

More exactly then, Na2B4O7, Borax or Sodium Borate or Sodium Pyroborate, or Sodium Tetraborate (the same compound under different names in different references) buffers optimally at 9.5 averaging 9 - 10 depending on concentration and other factors (see below).

 

Sodium Metaborate, NaBO2 buffers best at about 10.1. This is Kodalk and is obtained by fusing Sodium Carbonate and Borax with the evolution of carbon dioxide.

 

Sodium Perborate, another borate salt is not used in photography AFAIK. It decomposes in water to form borate salts and peroxide. It is a good oxygen bleach and detergent though.

 

To give a specific answer, the P122 developer, among others, used Kodalk and was at pH 10.1 at 20 deg C. This developer was incredibly stable to pH changes in open seasoned tanks. It was changed to Na2CO3 buffering in the EP3/EP2 developer for environmental reasons, among them concerns for the citrus industry as noted above.

 

In this instance, Kodalk was buffering at the top of its range and carbonate was at the low end of its range. The pH of a solution of Sodium Carbonate will be at 11.6, but this is not the optimum buffering position for it. It will drift downward due to absorption of CO2 from the air to form the bicarbonate in equillibrium. So, if you adjust the carbonate solution to 10.1 to start with, you are at the air equillibrium point of the developer for open tank. Kodalk or Borax will drift up due to the formation of sodium bicarbonate and sodium carbonate from air.

 

Bottom line rule of thumb. Any Borate or Carbonate developer that you want to have a good life, good capacity and be stable in open trays or tanks should buffer at about 10.0 at 20 deg C, and have at least 20 g/l of borate or carbonate to start with. More if possible.

 

The close pH values of the equillibria of mixed borates and carbonates in air make them ideal for developers. Phosphates have such a wide spread of pH values between the salts that the pH stability is poor. They have poor buffering curves at virtually any pH. I have noted elsewhere that C41 and RA developers at pH 10 can stand idle from time to time with no replenishment and survive with activity intact. The E4 developer disclosed on the EK web page, uses phosphate and does not survive idle times well due to pH drift.

 

Hope this helps you design better developers for B&W. Have fun guys.

 

Ron Mowrey

Peter,

 

Below are concentrations of reagents in my stock solutions A and B and in the working solution:

 

Sol. A contains 12 g VC and 0.25 g Ph. in 120 ml glycerine, an equivalent of 100 g VC and 2.08 g Ph. per 1 litre of concentrate.

 

Sol. B contains 25 g Na2CO3 in 1 litre of aqueous solution - this is self-explanatory.

 

My dev tank takes 400 ml of working solution to cover one 35 mm film. To prepare the working solution I take 5 ml A + 50 ml B + 350 water. This means that the respective concentrations of reagents are as follows:

 

VC - 1 + 80 - 1.25 g/l

Ph. - 1 + 80 - 0.026 g/l

 

Na2CO3 - 1 + 7 - 3.125 g/l

 

I carried out all the initial tests aimed at findind an optimum activator / concentrations using Foma 200, an inexpensive film of decent quality and, most of all, reliable. This is my primary testing material; the results can then be transferred to processing of more precious films using the time ratios taken from other developers I know well.

 

At 20C/68F I developed TRI X 400 (probably the new version) - 10.5 min

 

FP-4+ - 8 min.

 

FUJI NEOPAN 400 - 9.5 min

 

I was absolutely satisfied with the Tri-X and FP-4; the time for FUJI 400 appeared a little bit too short, even though I like 'thin' negatives. I shoot exclusively 35 mm films, use a Canon EOS 5, typically in shutter priority auto mode with evaluation meter pattern, introducing manual corrections whenever necessary and always adding 1/2 stop when I put an orange filter on my lens. I use prime lenses: a 50/1.8 and 24/2.8 for 90% of my photography. I make prints using a condenser enlarger with a six-element 50 mm Meogon lens, print on AGFA paper and seldom go beyond 8 x 10".

 

Hope this helps - regards - T.K.

The complete scoop on borax and borates may be obtained from http://www.borax.com. There you will find that borax buffers quite well between 9.2 and about 8.

There is a misconception among photographers about the meaning of metaborate-4mol and metaborate-8mol. The difference is not simply in the number of molecules of water of crystallization. The molecule of sodium metaborate-8 mol has twice as much of EVERYTHING, not just water. The upshot is that when you get sodium metaborate-4 mol, you are also getting sodium metaborate-8 mol. In water solution, the 4 mol is stable up to about 53 C, and the 8 mol is the form at higher temperatures.

 

The pH of metaborate solution is more dependent on concentration than that of borax solution, but the pH is also higher.

 

This and much more interesting information is to be had at www.borax.com. The fact that more boron is moved around the earth by weather than by all the mining we humans do is also interesting.

Patrick;

 

As I indicated in my answer above, the situation is made more complex by the ingredients in developers which either consume or release alkali or acid during keeping, along with atmospheric interactions.

 

Any alkaline solution will slowly turn into a carbonate. At certain pH values, buffer types, and buffer concentrations, the pH may go down, and at others it will go up.

 

A developer at pH 7 is rather useless, so it behooves one to mix a developer that will last and be active. Using Kodalk or carbonate, that optimum is at 10. Using borax, it would be 9, but it would drift more than the carbonate or Kodalk equivalent at 10. Believe me. I have run those tests over the period of a month or more in trays and deep tanks.

 

Ron Mowrey

Rowland, if a developer is mixed up on the spot and intended for one shot use, hence, there is no need for long life in a tank or storage, then how would that affect the choice of buffers? I'm not a chemist, so I find this discussion fascinating and educational. Thanks.

Steve;

 

For one shot developers, there is no overriding reason to use or not use any buffer except for speed, grain, sharpness, contrast and developability that satisfies you.

 

For developers with long shelf life, then buffer choice and amount become important, as well as solution pH. Kodalk or a carbonate at pH 10 would be my choice.

 

A borate or carbonate / bicarbonate at 9.5 would be my second choice.

 

My third choice would be an organic amine such as Triethanolamine adjusted to pH of about 8-9 (I'm not sure here, as I have run no experiments to verify this last one - but I have run the others above as well as the phosphates).

 

Patrick;

 

I forgot to mention that environmental studies in the early 60s linked citrus fruit tree problems with borates in effluents from color processing plants in the south and west. Ferricyanide was also linked to problems in various sites. EK began a large effort to eliminate borates and ferricyanide at that time. In 1965, I became involved in developing the carbonate buffered EP3/EP2 developer and the Blix. They were released in 1970.

 

So, notwithstanding aerial distribution of borates being significant but not being a problem, concentrated borate containing effluent could cause problems. A single darkroom would probably be no problem, but it might tax the local system in the south or west, causing undue levels of borate. IDK. I'm just giving out information here, not judging. I don't say it is a problem. I'm just citing past experience.

 

I personally use borate containing developers and keep borax and Kodalk on the shelf in my darkroom for mixing. They make fine developers.

 

Regards.

 

Ron Mowrey

Certainly the concentration of all the airborne borax in one place would create a Death Valley. It was a surprise to me, though, that boron is so common in the atmosphere. I was also surprised to learn that the concern over whether to buy 4 mol or 8 mol metaborate is unnecessary. The pH of Kodalk, nominally 10, is among those in the table of buffer solutions in the CRC handbook as a borax-NaOH combination.

 

I think that if there is going to be a major effect of consumer use of borax, it will be from the home laundries of the World. Many detergents contain it, and it is sold in large quantities for addition to detergents as a calcium chelating agent, a deodorant for diaper pails (who uses them nowadays?) and so on.

 

The chart in www.borax.com showing buffer capacities of various alkalis shows that borax outperforms carbonates and phosphates in resisting change of pH due to adding HCl when all are at 0.025 M.

 

There is also a brochure extolling the virtues of the ethanolamines, MEA, DEA and TEA. I think you will find it under Dow Chemicals. It has many charts.

Did I mention that ascorbic acid and phenidone dissolved in TEA make a good developer stock solution of long life. I think Sandy King mentioned it a while back. He adds a little bit of restrainer because the least bit of base fog increases exposure time considerably for his work with alternate processes.

 

By TEA, I mean triethanolamine, not Orange Pecoe or the like.

Patrick;

 

I believe that TEA (triethanol amine) has some antioxidant properties itself, although teas (orange pekoe etc.) have antioxidant properties as well in the human body.

 

Regarding TEA, it is just a suspicion with some weak evidence to base it on. I wonder if others have seen some indication? Having ascorbic acid present is no indicator, as it is a powerful antioxidant itself.

 

Without antioxidants in their varying forms, we would not have conventional photography as it is known today.

 

I prefer Earl Grey.

 

Ron Mowrey

Well, I hate to interrupt tea time, but I took Patrick's suggestion and tried a smaller amount of sulfite. I used 2 tbsps borax + 1/2 tsp sulfite + 20 ml of phenidone and Vit.C dissolved in glycol to a liter of water. This is basically the borax-only formula above with the addition of sulfite.

 

The sulfite appeared to have acted as a gentle restrainer. Fog is much reduced, and with it grain in the thin parts of the negative. Accutance may have improved a little too. No discernible effect in the high values, but the sulfite still seems like a worthwhile addition. Overall, the developer is now slightly less grainy than Acutol, has comparable accutance and much lower fog.

 

BTW, this developer project has damaged me a bit. Yesterday I was looking at a can of Sprite, and noted that the contents included both citric acid and sodium citrate. "How interesting," I thought, "they buffered the solution...."